from time import *
begin = time()
a = 2
while  a  <= 1000000 :
    flag = True
    b = 2
    while b <= a**0.5 :
        if a % b ==0 :
            flag = False
            break
        b += 1
    if flag :
        pass
        # print(a)
    a += 1
end = time()
print('程序运行花费的时间为：',end-begin,'s')
